Method of extracting gallium

Abstract

A method of removing gallium from tin, lead or tin-lead alloy in which the molten metal containing gallium is treated with a molten flux of alkali metal hydroxide, alkali metal carbonate or a mixture of such constituents where the alkali metal is lithium, sodium, potassium or a mixture of these. Preferably the metal and flux are stirred together, then separated, and the flux dissolved in water and gallium recovered from the solution by electrolysis.

We claim: 
     
       1. A method of removing gallium from a metal selected from the group consisting of tin, lead, and tin-lead alloy which comprises treating the metal in molten form with a molten flux consisting essentially of alkali metal hydroxide, and removing the flux containing gallium from the remainder of the metal. 
     
     
       2. A method according to claim 1 in which the flux additionally includes alkali metal chloride as a non-fuming melting point depressant. 
     
     
       3. A method according to claim 1 in which the molten flux consists of 100% sodium hydroxide. 
     
     
       4. A method according to claim 1 which comprises maintaining the molten flux and the molten metal in the temperature range 220° to 860°C. 
     
     
       5. A method according to claim 1 which includes stirring the molten flux and molten metal to improve the contact therebetween. 
     
     
       6. A method according to claim 1, in which the flux is cooled to a solid state and the metal remainder poured off while still molten. 
     
     
       7. A method according to claim 1, which comprises dissolving the separated flux in water to produce an alkali metal gallate solution. 
     
     
       8. A method according to claim 7, which comprises removing the gallium from said solution by electrolysis between suitable inert electrodes.